1. Field of the Invention
The present invention relates to a tray for containing parts for storage and transportation. More particularly, the present invention relates to a tray for containing parts, such as IC chips, for storage and transportation and being conveniently serviceable for automatically mounting parts on a wiring board or the like.
2. Description of the Related Art
Referring to FIG. 15 showing a conventional tray 100 by way of example, the tray 100 is provided in its upper surface with a plurality of pockets 101 for containing electronic parts, arranged in rows and columns, and a plurality of positioning holes 102 in a predetermined positional relation with the pockets 101.
Referring to FIG. 16 showing a conventional electronic part mounting system in a schematic view, a mounting unit A mounts electronic parts on a wiring board or the like to be incorporated into an electronic apparatus. A handling unit B is installed on the receiving side of the mounting unit A. A plurality of trays containing electronic parts are stacked in a region E in the handling unit B. A handling device provided with a handling head C is installed in the handling unit B. In FIG. 16, components of the handling device other than the handling head C are not shown. The handling head is able to move in the directions of the arrow X and the arrow Y along an X-axis guide rail and a Y-axis guide rail.
The handling device detects the positioning hole 102 of the tray 100 by a sensor, not shown, moves the handling head C to a position indicated by XY coordinates based on position information provided by the sensor, and then moves the handling head C in a Z-axis direction, i.e., a direction perpendicular to the paper, to pick up the electronic part by suction from the tray 100. Then, the handling head C of the handling device holding the electronic part carries to a position under a positioning table F. Then, the positioning table F transfers the electronic part to the mounting unit A. After all the electronic parts contained in the tray 100 have been taken out, the empty tray 100 is transferred by an empty tray returning device, not shown, to an empty tray storage unit D disposed on the tray returning side of the handling unit B.
The handling unit B of this conventional electronic part mounting system must move the handling head C in the three directions, i.e., the X-axis direction, the Y-axis direction and the Z-axis direction. Since operations for moving the handling head C in the three directions cannot be synchronously carried out, the electronic part handling operation cannot be satisfactorily efficiently achieved. The rigidity of the guide rails must be enhanced to improve positioning accuracy in positioning the handling head C, which involves increase in the dimensions and weight, and structural complication of the guide rails and a driving mechanism for driving the guide rails, and, consequently, increases the cost of the electronic part mounting system. Furthermore, the electronic part mounting work must be interrupted during an empty tray returning operation, which reduces the efficiency of the electronic part mounting work.
As shown in FIG. 15, the conventional tray 100 is formed so as to contain a plurality of electronic parts (usually about twenty electronic parts). Therefore, the tray 100 not fully loaded is shipped to a customer when providing the customer with a few sample electronic parts less than the capacity of the tray 100, which needs distribution cost more then is necessary.